Automotive air conditioning compressor

ABSTRACT

In preferred form, a four cylinder radial compressor which is operated by an eccentric slider drive mechanism. Two pairs of cylinder bores are radially spaced 90* apart with the center lines of the cylinders lying in a common plane. Opposed pairs of pistons in the bores are linked together with sheet metal links that apply piston preload to an eccentric slider block for high speed continuous operation. The compressor is lubricated by oil that is carried by the refrigerant to the compressor. The refrigerant gas enters the compressor at the rear of the drive shaft and the suction return is diverted into the cylinder housing while the heavier oil enters an aligned hole in the shaft for distribution to the eccentric bearing and eccentric slider of the drive mechanism.

United States Patent Hutchins et a]. [4 1 Aug. 22, 1972 [54] AUTOMOTIVEAIR CONDITIONING I 1,631,425 6/1927 Marcus et a1 ..417/273 COMPRESSOR3,093,301 6/1963 Mitchell ..417/273 [72] Inventors: Everett C. Hutchins'Gary Spencer; Marion K. Tinker, an of Prlrnary Examtner-Carlton R.Croyle Dayton, Ohio Assistant Exarruner-John J. Vrablik Att0rney-W. S.Pettigrew and J. C. Evans [73] Ass1gnee: General Motors Corporation,

Detroit, Mich. I 57 ST [22] Filed: 1970 In preferred form, a fourcylinder radial compressor 211 App} 7 410 which ,is operated by aneccentric slider drive mechanism. Two pairs of cylinder bores areradially spaced 90 apart with the center lines of the cylinders [52] US.Cl ..417/273, 417/523 lying in a Common plane. Opposed pairs of pistonsin [51] P Cl F04b 27/04 F04b 21/04 the bores are linked together withsheet metal links [58] Fleld of Search ..417/273, 523, 534-537; thatapply piston preload to an eccentric Slider block 92,138 for high speedcontinuous operation. The compressor is lubricated by oil that iscarried by the refrigerant to [56] References cued the compressor. Therefrigerant gas enters the com- UNITED STATES PATENTS pressor at therear of the drive shaft and the suction return is diverted into thecylinder housing while the 3,174,436 3/1965 Wanner ..417/273 heavier oi]enters an aligned hole inthe Shaft for 2,450,248 9/1948 Morgan et"417/273 tribution to the eccentric bearing and eccentric slider1,023,685 4/ 1912 Ruwell ..417/273 of the drive mechanism 1 3,456,8747/1969 Graper ..417/534 2,529,996 11/1950 Browne ..417/273 4 Claims, 9Drawing Figures Z5 8 i= 243246 zaz 5 n 24-? 5 g Q6 I: 7 g, 9x

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4 I w w 1 121 as w w in a 7 ll 56 a /Z T- i I Z w mmtmuczzmz 3.685323SHEET 2 0f 3 IN VEN TORS ivezef/ fluid/2:225, 5054/ a: James: 6:

AT TOR/VEY AUTOMOTIVE AIR CONDITIONING COMPRESSOR This invention relatesto rotary machines and more particularly to compressors having radialbores and radially reciprocated pistons therein driven by a common drivemechanism.

In automotive air conditioning systems it is desirable to have a lightweight compressor that can be connected to the engine block of theautomobile and driven at a continuous high speed of operation by thebelt that drives the engine cooling fan.

At such high speed operation it is desirable to have a built-inlubricant supply system in the compressor and additionally it isdesirable that the radial piston units be operated by a drive mechanismthat will prevent wear producing tipping movement of the reciprocatingpistons in the cylinder bores.

Accordingly, an object of the present invention is to provide a highspeed rotary machine which includes a plurality of radially locatedpiston cylinder units driven by a common drive mechanism wherein meansare provided to prevent each of a plurality of the pistons from beingtipped with respect to the cylinder bores during compressor operation.

Yet another object of the present invention is to provide a compact highspeed compressor by locating a plurality of radial piston and cylinderunits in a common plane and driving them by a common slider drivemechanism that prevents the pistons from tipping with respect to thecylinder units during high speed operation and wherein the pistons areseparate components in the assembly and tied together by means ofseparate preloading links that maintain a tight fitting, no tip, closetolerance relationship between the common drive mechanism and thepistons during high speed operation.

Yet another object of the present invention is to provide a compactcompressor configuration for use in automotive air conditioning systemswherein a shaft bearing housing has a suction port therein in axialalignment with a large diameter opening in the end of the shaft todirect suction gas entrained oil between sliding surfaces in componentparts of the drive mechanism and wherein the bearing housing includesmeans for diverting the refrigerant into a low pressure region in thecenter of the compressor and wherein the bearing housing includesdischarge port means for communicating each of a plurality of radiallylocated circum ferentially spaced cylinder bores for directingcompressed refrigerant from the compact compressor arrangement.

These and other objects of the present invention are found in oneworking embodiment which includes a cylinder body having four cylinderbores radially spaced 90 apart. All of the cylinder bores have theircenter lines lying in a common plane. An iron plated die cast aluminumpiston is located in each of the bores for sliding reciprocatingmovement therein during compressor operation. Each of the pistons aredriven by a common eccentric slider block.

Opposing pairs of the pistons are linked together with sheet metal linksthat apply a piston preload to the eccentric slider block which isactuated by a common eccentric on a drive shaft. The drive shaft issupported by a rear bearing plate and a front bearing plate on thecylinder block. Suction gas enters the compressor through the rear platewhere it is diverted into the cylinder body. Heavier oil in thereturning refrigerant enters a hole in the shaft which is aligned withthe suction port. Oil collected in the hole is distributed to aneccentric bearing which supports the eccentric slider block on the shafteccentric.

Suction gas enters the compression chamber through suction ports in thetop of the pistons. Suction reeds are attached to the top of thepistons. Refrigerant gas is discharged through a valve plate in each ofthe cylinder heads and is delivered to a manifold in the rear platethrough a plurality of circumferentially spaced holes in the cylinderbody, all located radially outwardly of the suction opening.

The arrangement enables the compressor to be operated at a high speed ofoperation in a range of 5500 continuous rpms to 8500 rpm a maximuminstantaneous speed.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIG. 1 is a vertical sectional view taken along line 11 of FIG. 2looking in the direction of the arrows;

FIG. 2 is a view in rear elevation of the compressor partly broken awayand partly in section;

FIG. 3 is a horizontal sectional view taken along the line 3-3 of FIG.1;

FIG. 4 is a horizontal sectional view taken along the line 4-4 of FIG. 1looking in the direction of the arrows;

FIG. 5 is an enlarged fragmentary vertical sectional view taken alongthe line 5-5 of FIG. 1 looking in the direction of the arrows;

FIG. 6 is a vertical sectional view taken along the line 6-6 of FIG. 1looking in the direction of the arrows;

FIG. 7 is a horizontal sectional view taken along the line 77 of FIG. 6looking in the direction of the arrows;

FIG. 8 is a vertical sectional view along the line 88 of FIG. 1 lookingin the direction of the arrows; and

FIG. 9 is an elevational view of an eccentric slider block in thepresent invention.

Referring not to the drawings, in FIGS. 1 and 2, a compact compressor 10is illustrated which includes a central block or cylinder body 12 havingfour radially spaced bores l4, 16, 18 and 20.

The bores 14 and 16 are formed coaxially of one another in the body andalong an axis which is perpendicular to the axis of coaxially alignedbores 18 and 20.

In the illustrated arrangement the rear of the compressor body includesa central opening or suction space 22 therein which serves as the inletto each of the cylinder bores 14 through 20.

As is best seen in FIG. 8, the rear of the body further includes aplurality of arcuate openings 24, 26, 28 and 30 therein which areseparated by partition members 32.

Each of the arcuate openings communicates with a discharge bore 36 inbody 12 which is adapted to be communicated with an adjacent one of thecylinder bores at the discharge end thereof.

' port 50 that is adapted to be connected to a return conduit or suctionhose of a refrigerant system of the type found in automotive airconditioning systems.

Between the bore 48 and suction opening 50 is a transition bore 52 whichcommunicates with two spaced holes 54, 56 each of which intersects the,transition bore 52 at an acute angle A shown in FIG. 7. They alsocommunicate with the suction opening 22 in the compressor body 12 oneither side of the sleeve bore 48 therein.

Additionally, the rear bearing housing 44 includes an annular recess 58formed in the inside face thereof continuously therearound tocommunicate each of the arcuate discharge openings in the compressorbody with a discharge port 60 which is adapted to be connected toa'supply line from the compressor to a condenser unit in the refrigerantsystem.

In the illustrated arrangement, the arcuate recess 58 communicates witha plurality of discharge muffler cavities 62, 64, 66, 68, 70, 72 and 74,each of which are separated by a reinforcing rib 76 formed as anintegral part of the housing 44 as is best illustrated in FIG. 6.

Additionally, the housing includes an opening 78 which is adapted tocommunicate the low pressure side of the compressor with a pressureswitch cavity 80 in which a diaphragm switch operated component can belocated to control the operation of the refrigerant system. A pressuregauge tap 81 is also shown inFIG. 6.

The housing 44 includes a plurality of like circumferentially spacedconnecting lugs 79 thereon which have connecting screws 83 directedtherethrough into threaded engagement with tapped openings 82 in thehousing at circumferential point at the outer periphery thereof as bestseen in FIG. 8. g

A gasket seal 84 is fastened between the inside face of the bearinghousing 44 at the outer periphery thereof around the lug 79 thereon andthe peripheral surface of the body 12 to seal between the inlet andoutlet passageways in the housing 44 and the body 12.

On the opposite end of the body a front bearing housing 86 has aperipheral shoulder 88 formed thereon which fits within an; end opening90 on the body 12.

The front bearing housing 86 includes a seal cavity 92 therein which isformed by an axially outwardly directed tubular extension 94. The outerperiphery of the housing 86 includes a plurality of connecting lugs 96thereon which have screws 98 directed therethrough into threadedengagement with the central body 12 to hold an annular gasket seal 100in sealing engagement between the body 12 and the bearing housing at theopening 90 therein.

A drive shaft 102 is directed through the body 12. It includes anoutboard end extension 104 thereon which is adapted to be connected to adrive source for high speed operation. A rear end 106 of theshaft issupportingly received by a bearing assembly 108 seated within the sleevebore 48 in the rear housing 44.

As is best seen in FIG. 5, the shaft includes a large diameter opening110 on the front end thereof which is aligned coaxially of the suctionport 50 and the transition bore 52. The opening 1 10 in turn is incornmunicar I tion with an oil feed passageway 1 12 formed longitu-,

dinally through shaft 102 that is intersected by a bore 114 extendingradially outwardly of the passageway 112 to intersect the outer surface116 of an eccentric 118 integrally formed on the shaft 102. In theillustrated arrangement the eccentric 118 has three holes 120, 122, 124formed therethrough to balance the shaft 102.

Additionally, the shaft 102 has a second bearing surface 126 thereonwhich is supportingly received in a bearing assembly 128 that is fittedwithin a sleeve bore 130 in housing 86. Bore 130 is aligned coaxiallywith the bore 48 thereby to support the shaft 102 for rota-.

tion with respect to the central compressor body 12 so as to move theeccentric 118 therein with respect to each of the cylinder bores.

The eccentric 118 forms partof an improved high speed compressor sliderdrive mechanism 132.

The eccentric slider drive mechanism 132 more par: ticularly includes aneedle bearing assembly 131 which has the inner race thereof fit on theouter'periphery 116 of the eccentric 118 in the outer race thereof fitwith one another and slidably received within the cylinder bores 12, 14for opposite reciprocation therein during operation of the compressor. l

' Additionally, the eccentric slider block 134 includes a second pair offlat spaced parallel surfaces 152, 154 I thereon which are supportinglyreceived in grooves 156, 158 located in opposed pistons 160, 162,respectively.

The opposed pistons 160, 162 are slidably supportingly received forreciprocation in the coaxially aligned cylinders 18, 20 which arelocated on an axis perpendicular to that of the axis formed through theY coaxially aligned cylinders 14, 16.

In accordance with one principle of the present invention, all of thepiston cylinder units are located in a common plane and driven by acommon drivemechanism to produce a reduced outer dimensional compactnesscompared to the total volumetric output thereof.

One important aspect of the present invention is the manner in which theopposed pistons are'tied together and balanced with respect to theeccentric compressor drive mechanism 132 to produce an improved highspeed range of operation of the device.

To accomplish such operation, the shaft is maintained in its supportedrelationship with respect to the sleeve bearings 108,128 by means of afirst bearing thrust washer 160 at one end of the shaft which is locatedbetween a hub extension 162 and a shaft counterweight 164 which seatsagainst a shaft shoulder 166.

The opposed pistons 148, are coaxially aligned On the opposite end ofthe shaft a Belleville type thrust washer 168 is located between a hubextension 170 on the front bearing housing 86 and a counterweight 172which seats against a shaft shoulder 174.

The counterweights and drilled eccentric serve to carefully balance thehigh speed shaft 102 and the bearing arrangement define a stableplatform.

Additionally, in order to further enhance the dynamic stability of themechanism while operating at high speed operation, in accordance withcertain principles of the invention the opposed parallel surfaces 142,143 are maintained in a close tolerance relationship with the slidergrooves 144, 146 on the pistons 148, 150 be a pair of spaced connectorlinks 176, 178 of sheet metal material.

The link 176 includes a central portion 180 which is bent to one side ofthe drive shaft 126 is best illustrated in FIG. 2. It is joined tooffset ends 182, 184 that are fastened to the end of a cross pin 186through piston 148 and a cross pin 188 through piston 150, respectively.

The connecting link 178 includes a central portion 190 which is bulgedto one side of the shaft 126 in the opposite direction to the centralportion 180 of link 176. It includes opposite ends 192, 194 thereonwhich are press fit over the opposite end of the cross pin 186 and thecross pin 188.

Together the links 176, 178 are prestressed during the assembly of thecompressor to cause the slider grooves 144, 146 on the pistons 148, 150to be held in close sliding fit relationship with the parallel surfaces142, 143 on the slider block.

One feature of the slider surfaces 142, 143 and the grooves 144, 146 isthat they are formed fiat with respect to one another and togetherdefine a moving, sliding flat surface that enables the supported pistonthereon to reciprocate within its cylinder bore without being tippedwith respect thereto on opposite reciprocation of the piston within theunit.

The provision of separate pistons and connecting links has a furtheradvantage in that it enables four piston units to be driven by a commonslider block eccentric at high speeds. This is in contrast toarrangements where a slider block mechanism is located within adouble-ended unitary piston which is reciprocated within opposedcylinder units as for example of the type shown in US. Pat. No.2,031,940 to Drysdale. In this arrangement, the inclusion of adouble-ended piston prevents location of an additional pair of opposedpiston cylinder units at 90 with respect to a, first air. v p In thisarrangement, the-opposed pistons 160, 162 are interconnected by a secondpair of connecting links 196, 198 which are located axially of the shaftbetween the outer connecting links 176, 178 and the axial end surfaceson the eccentric l 18 as is best seen in FIG. 1.

The connecting link 196 includes a central portion 200 thereon bulgedoutwardly of the shaft 126 to the same extent as are central portions180, 190. Offset ends 202, 204 on the link 198 are press fit over crosspins 206, 208 directed through the ends of pistons 160, 162,respectively.

The connecting link 198 is located between the eccentric 118 and thelink 178. It includes a central portion 212 and end portions 214,216which are connected to the opposite ends of the cross pins 206, 208. Asin the case of the pistons 148, 150, the connecting links 198, 210 arepreloaded to draw the axially aligned piston 161, 162 together so as tohold them in a close tolerance sliding fit relationship with the grooves156, 158 therein and the opposed parallel surfaces 152, 154 on theslider block 134. The respective sliding surfaces thus serve as a stableplatform during compressor operation to prevent tipping of the pistonswith respect to their cylinder bores.

In addition to the dynamic stability the compressor includes features tomaintain a uniform suction and discharge action through the dischargeport 60 and the suction port 50 of the rear bearing housing 44. Suchrefrigerant flow is accomplished through a flow path which separates thelubricant from the circulating refrigerant gas. Furthermore, the highspeed shaft 102 has the extension 104 thereon sealed by a rotary sealassembly 218 which is operative to prevent gas leakage through the shaftbore 92 during such operation. More particularly, the rotary sealassembly includes a rotary seal element 220 which is connected forrotation with the shaft 102 through a seal retainer 222 that is securedon a shoulder 224 of the shaft. The rotary spring is spring biasedoutwardly of the retainer 222 coaxially along the shaft 102 by coilspring 226. The biased element 220 bears against a sealing surface 228constituted by an annular ring that is held in place by a snap ring 230within the housing 178.

The refrigerant circuit for all of the piston cylinder units isidentical. For purposes of this description, reference will be only hadto that through the piston unit 148.

The component parts of the refrigerant circuit are the'same for each ofthe piston cylinder bore units. It includes an annular seal 232 in theperiphery of each of the pistons which is biased radially outwardly toseal against the inside surface of the cylinder bore to preventbypassing of the piston.

Additionally, each of the pistons includes a plurality of suction ports234 formed in the head thereof at uniformly spaced circumferentialpoints therealong.

A suction reed valve 236 includes a center segment 238 thereon securedto the top of the piston by a screw retainer 240. It further includes anoutwardly located continuously formed peripheral ring 242 which coverseach of the suction ports 234.

The upper open end of each of the bores is closed by a discharge valveplate 244.

It is sealed with respect to the housing or compressor body 12 of thebore therein by a valve plate gasket 245.

The valve plate includes a plurality of discharge ports 246 thereinwhich are best illustrated in FIG. 3, as being formed continuouslyaround the plate 244 at equally spaced circumferential points thereon.

These discharge ports are covered by a discharge reed valve 248 that hasa center portion 250 thereon secured to the center of the plate 244 by arivet 252 having the head thereof 254 upset against the underside of theplate 244.

The discharge reed valve 248 further includes an outer peripheral ring256 thereon which covers the ports when the valve is closed. A back-upplate 257 is fastened by rivet 252 toplate 244.

A cylinder head 258 is located on each of the plates 244 in coveringrelationship therewith. Each of the heads 258 includes a plurality ofopenings 260 therethrough which receive connecting screws 262 that aredirected through like openings 263 in the discharge plate into tappedholes in the compressor body 12 around the bore therein.

Additionally, the cylinder head 258 includes a recess 265 thereon whichincludes a side segment 264 that overlies a crossover passageway 266 inthe discharge plate which leads to a discharge bore 36 in the body 12.

The cylinder head is sealed with respect to the upper surface of thedischarge plate by a head gasket 270.

Operation of the compressor includes a continuous suction intake anddischarge of refrigerant ga's to produce a relatively constant torque onthe drive shaft clockwise direction as viewed in FIG. 2, the eccentric-118 as shown in FIGS. 1 and 2 locates the opposed pistons 148 and 150 atthe beginning of a discharge strokeand at the end of the dischargestroke, respectively. Simultaneously, the opposed pistons 160, 162 arelocated at intermediate positions within the bores through anintermediate point of a suction stroke and an intermediate point of adischarge stroke respectively. Further, clockwise movement will causethe following to occur:

The piston 148 will move upwardly within the bore 12 to dischargerefrigerant between the top of the piston 148 and the discharge platethence through the opening or recess of the cylinder head and out thedischarge bore 36 into the arcuate recess 58 thence to the dischargeport 60. At the same time, refrigerant gas is drawn through the suctionport 48 and the central opening 22 into theinside of'the body 12 whereit passes across the suction reed valve on the piston 150 into theincreasing volume formed between the piston 150 and the bore 16. v 7

When the eccentric is moved 90 from the positio shown in FIG. 2 in aclockwise direction, the opposed parallel surfaces 142, 143 on theslider block 134 are positioned equidistantly with respect to the centerline of the shaft thereby to position the piston unit 148, 146 atmidpoint within their bores. At the same time the eccentric has movedthe slider block 134 to cause the opposed parallel surfaces 152, 154thereon to position the piston 160 at the end of its discharge strokeand the piston 162 at the end of its suction stroke. Furthercounterclockwise movement of 90 will move the piston 148 to the end ofits discharge stroke and the piston 150 to the beginning of its suctionstroke.

A further clockwise movement of 90 will cause the eccentric to bealigned with the piston 162 moving it to the end of its discharge strokeand the piston 160 to the end of its suction stroke leaving the'pistons148, 150 at their intermediate position. Then the eccentric will belocated in alignment with the piston 150 through a further clockwisemovement of 90 to return the pistons to their positions shown in FIGS. 1and 2.

Thus, the location of the eccentric will produce a continuous andprogressive shifting movement of the pairs of parallel surfaces to causeeach of the pistons to move completely upwardly within its bore and thenreciprocate back to a suction position wherein the low point on theeccentric is in alignment with that piston. The motion is harmonic innature and continuous to maintain a uniform torque on the shah.

pression strokes and discharge strokes each rotation of the shaft.

During this movement the respective sliding surfaces between the sliderblock and the pistons are moved through a sliding transverse movementwith respect to each other thereby to define a continuous flat surfaceduring the suction return. Refrigerant gases passing 7 through thesuction port 50 enters the transition bore 52 .and then pass through theangularly formed holes 54, 56 and are thence directed into the interiorof the compressor body 12 through the central end opening 22 therein.The light gas freely flows through the angular openings 54, 56.

Heavier oil particles, however, continue to-flow in the same directionthrough the suction port 50 and the transition bore 52 thereby to becollected by the large diameter opening 110 for flow through thepreviously described oil distribution system thereby to completelylubricate the friction surfaces between the outer surface 116 of theeccentric; the component parts of the eccentric bearing 131 and thegrooves in each of the pistons. y

In one working embodiment of the present invention the compressor has acapacity of 8.5 cubic inches of displacement. This is produced by fourcylinder bores cylinder head Part Material cylinder body 12 rear bearinghousing 44 front bearing housing 86 pistons 148, 150, 160, 162 eccentricslider block 134 shaft 102 die cast aluminum die cast aluminum die castaluminum iron plated die cast aluminum hardened steel I localizedinduction hardened I q ssi sl Also in addition to having extremecompactness the overall weight of the compressor is low which makes itespecially suitable for connection'to small displacement internalcombustion engines.

. While the embodiments of the present invention as herein disclosedconstitute a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

l. A rotary machine comprising a cylinder block having four cylinderbores formed therein, each of said cylinder bores having theircenterline located in a common plane, a first pair of said cylinderbores being located coaxially with one another and at a perpendicularrelationship with a second pair of said bores, a rear bearing housing onsaid cylinder block, a front bearing housing on said block, a rotaryshaft directed through said block having the opposite ends thereonsupported by said front and rear bearing housings, said shaft having anextension thereon adapted to extend outwardly of said front bearinghousing for connection to a drive source, an eccentric throw on saidshaft, said eccentric throw having an outer peripheral surface thereonlocated in said common plane of the centerlines of said cylinder bores,an annular needle bearing on said eccentric, a slider block slidablysupported by said annular needle bearing, said slider block having afirst pair of parallel sides thereon located coaxially of said firstpair of bores and a second set of parallel sides thereon located incoaxial alignment with said second pair of bores, a piston in each ofsaid bores, each of said pistons having a base portion thereon with agroove therein in which is supportingly received one of said parallelsurfaces on said slider block, said eccentric throw being rotated bysaid shaft within said needle bearing to cause axial movement of saidslider block with respect to each of said cylinder bores to cause eachof said pistons to reciprocate within one of said cylinder bores, saidslider block being moved by rotation of said eccentric laterally withrespect to the groove in each of said pistons to provide a full-bearingsupport for said piston during reciprocation thereof within said borethereby to prevent tilting movement of said pistons during reciprocablemovement thereof within said bores, and means to preload each of saidpiston base portions against one of said parallel sides of said sliderblock including a first pair of spaced apart flat sheet metal linkslocated on opposite sides of said slider block, each of said linkshaving a central portion offset from said shaft and opposite endscolinear with each other and with the axis of said shaft, means joiningsaid opposite ends to said first pair of pistons together, each of saidlinks being pre-stressed to a predetermined length between its oppositeends to locate said pistons to hold the grooved base portions of saidfirst pistons in close sliding fit engagement with said first pair ofparallel sides of said slider block, said preloading means including asecond pair of flat sheet metal links located on opposite sides of saidslider block, each of said links having a central portion offset fromsaid shaft andopposite ends colinear with each other and with the axisof said shaft, means joining said opposite ends of said second pair oflinks to said second pair of pistons, each of said links beingpre-stressed to a predetermined length between its opposite ends tolocate said pistons to hold the grooved base portions of said secondpair of pistons in close sliding fit engagement with said second pair ofparallel sides on said slider block there to maintain said slider blockand the grooves in said piston continuously in close sliding engagementupon opposite reciprocation of said pistons within said cylinder bores.

2. In a reciprocating compressor the combination of a body with aplurality of cylindrical bores therein, a suction space in said body, aplurality of discharge l 0 passageways formed in said body radiallyoutwardly of said suction space' in spaced circumferential relationshiptherearound, a rear bearing housing secured to said body for closingsaid suction space therein, a front bearing housing secured to saidhousing, a rotary drive shaft, bearing means in said front bearinghousing and said rear bearing housing for supporting said shaft withinsaid body for rotation with respect thereto, an eccentric throw securedto said shaft for rotation therewith, said throw being located withinsaid suction space, a bearing supported on the outer surface of saidthrow rotatable therewith, a slider block having a central openingreceiving said bearing, said bearing and throw driving said blockthrough oscillating movement with respect to the longitudinal axis ofsaid drive shaft, said block including a plurality of flat surfaces onthe outer periphery thereof, a piston in each of said cylinder "boreshaving a base portion thereon formed 'as a flat surface, each of saidbase portion surfaces engaging one of said slider surfaces on saidslider block for sliding movement therebetween upon oscillatory movementof said slider block about the longitudinal axis of said drive shaft, apin directed through each of said pistons, a link member having one endthereof connected to one end of a pin in one of said pistons and havingthe opposite end thereof connected to the end of a pin in another one ofsaid pistons, a second link member having one end thereof connected tothe op posite end of the pin in the one piston and the opposite endthereof connected to the opposite end of the pin in the another one ofsaid pistons, said first and second links having a central portionthereon offset from the connected ends of each of said links on eitherside of said shaft, each of said links prestressed between its connectedends to a length to hold said first and second pistons against saidslider block to maintain a close sliding fit therebetween upon rotationof the shaft, said slider block surfaces moving axially of and laterallyof each of said bores during oscillation of said slider block about saiddrive shaft during rotation thereof to produce reciprocation of saidfirst piston into and out of its cylinder bore in a direction oppositeto the reciprocation of said second piston within its cylinder bore andserving to define a flat surface support for said pistons at the basethereof to prevent tipping movement of said pistons with respect to saidcylinder bores during opposite reciprocation of said pistons within saidbores.

3. In a reciprocating compressor the combination of, a central body, aplurality of radially outwardly directed cylinder bores in said bodyspaced apart, the centerline of each of said cylinder bores lying in acommon plane, a separate piston in each of said cylinder bores, a rotarydrive shaft for said pistons, means for supporting said drive shaft forrotation with respect to said body, a common eccentric on said shaft foractuating each of said pistons, a slider block operated by said commoneccentric, a flat surface on said slider block in alignment with each ofsaid pistons, means forming a flat follower surface on each of saidpistons supportingly engaged by said flat surface on said slider block,a first pair of said pistons located coaxially of one another, a firstpair of flat sheet metal connecting links located on each side of saidsecond pair of pistons, each of said links having a center porspacedcircumferential I means for communicating said suction space and saiddischarge openings with said bores, a rear bearing tion offset from saidshaft and ends secured to said first pair of pistons, each of said linksbeing prestressed to a predetermined length between its opposite ends,to locate said pistons together against said slider block, a second pairof said pistons located coaxially of one another and at right angles tosaid first pair, a second pair of flat sheet metal connecting linkslocated on each side of said second pair of pistons, each of said linkshaving a center portion offset from said shaft and ends secured to saidsecond pair of pistons, each of said links being prestressed to apredetermined length between its opposite ends to locate said secondpair of pistons together against said slider block, said first andsecond pairs of sheet metal connecting links maintaining the followersurface on each of said pistons in close sliding fit relationship withthe flat surfaces on said said shafts for causing opposite reciprocationof each of said'pistons within one of said radial bores during rotationof said shaft, said drive means including an eccentric throw on saidshaft, a bearing on the outer periphery of said throw, a slider blocksupportingly received on the bearing havinga portion thereon slidablyengaging said pistons at an interface for caus-- housing formedcoaxially of the end of said shaft supported by said rear bearinghousing, said rear bearing housing having a transition bore aligned withsaid suction port for reducing velocity of inlet gas from said suctionport, a largediameter opening in the supported slider block to produceopposite reciprocation of each of said pistons within its cylinder boreupon rotation of said shaft, said slider block flat surface movinglaterally and axially of said piston during reciprocationthereof todefine a stable supporting surface for said piston to prevent tippingmovements thereof with respect to the cylinder bore during oppositereciprocation of said first and second piston pairs.

4. A compressor having a central body with a plurality of radiallyoutwardly directed cylinder bores therein, a piston in each of saidbores slidably reciprocable with respect thereto, said body including asuction space located centrally thereof and radially inwardly of ,saidbores, a plurality of discharge openings in said body located radiallyoutwardly of said suction space in relationship therearound,

housing secured to said body including means thereon closing saidsuction space in said body, a front bearing housing on said body, arotary shaft having the opposite ends thereof supportingly received insaid rear and front bearing housings, drive means for operativelyconnecting each of said pistons in said radial bores to end of saidrotary shaft coaxially aligned with said suction port and transitionbore and facing'in the direction of inlet gas flow through said suctionport to separate and intercept lubricants suspended therein, alongitudinal passageway in said shaft for receiving separated lubricantfrom the large diameter opening, a transverse passageway in said shaftreceiving oil from the longitudinal passageway to said bearing, andbeing rotated by sh to distribute oil in a ra 'al di ection, s 'd s 1 erb ock including a p uralrty o radial y outwar y directed openingstherein for directing oil from said bearing to the sliding interfacebetween said slider block and each of said pistons and into said suctionat an angle with respect to the longitudinal axis of said transitionbore on either side thereof for receiving gas from the suction port anddirecting it to the suction space in said body, and suction valve meansin each of said pistons for passage of gas and lubricant from-the

1. A rotary machine comprising a cylinder block having four cylinderbores formed therein, each of said cylinder bores having theircenterline located in a common plane, a first pair of said cylinderbores being located coaxially with one another and at a perpendicularrelationship with a second pair of said bores, a rear bearing housing onsaid cylinder block, a front bearing housing on said block, a rotaryshaft directed through said block having the opposite ends thereonsupported by said front and rear bearing housings, said shaft having anextension thereon adapted to extend outwardly of said front bearinghousing for connection to a drive source, an eccentric throw on saidshaft, said eccentric throw having an outer peripheral surface thereonlocated in said common plane of the centerlines of said cylinder bores,an annular needle bearing on said eccentric, a slider block slidablysupported by said annular needle bearing, said slider block having afirst pair of parallel sides thereon located coaxially of said firstpair of bores and a second set of parallel sides thereon located incoaxial alignment with said second pair of bores, a piston in each ofsaid bores, each of said pistons having a base portion thereon with agroove therein in which is supportingly received one of said parallelsurfaces on said slider block, said eccentric throw being rotated bysaid shaft within said needle bearing to cause axial movement of saidslider block with respect to each of said cylinder bores to cause eachof said pistons to reciprocate within one of said cylinder bores, saidslider block being moved by rotation of said eccentric laterally withrespect to the groove in each of said pistons to provide a full-bearingsupport for said piston during reciprocation thereof within said borethereby to prevent tilting movement of said pistons during reciprocablemovement thereof within said bores, and means to preload each of saidpiston base portions against one of said parallel sides of said sliderblock including a first pair of spaced apart flat sheet metal linkslocated on opposite sides of said slider block, each of said linkshaving a central portion offset from said shaft and opposite endscolinear with each other and with the axis of said shaft, means joiningsaid opposite ends to said first pair of pistons together, each of saidlinks being pre-stressed to a predetermined length between its oppositeends to locate said pistons to hold the grooved base portions of saidfirst pistons in close sliding fit engagement with said first pair ofparallel sides of said slider block, said preloading means including asecond pair of flat sheet metal links located on opposite sides of saidslider block, each of said links having a central portion offset fromsaid shaft and opposite ends colinear with each other and with the axisof said shaft, means joining said opposite ends of said second pair oflinks to said second pair of pistons, each of said links beingpre-stressed to a predetermined length between its opposite ends tolocate said pistons to hold the grooved base portions of said secondpair of pistons in close sliding fit engagement with said second pair ofparallel sides on said slider block there to maintain said slider blockand the grooves in said piston continuously in close sliding engagementupon opposite reciprocation of said pistons within said cylinder bores.2. In a reciprocating compressor the combination of a body with aplurality of cylindrical bores therein, a suction space in said body, aplurality of discharge passageways formed in said body radiallyoutwardly of said suction space in spaced circumferential relationshiptherearound, a rear bearing housing secured to said body for closingsaid suction space therein, a front bearing housing secured to saidhousing, a rotary drive shaft, bearing means in said front bearinghousing and said rear bearing housing for supporting said shaft withinsaid body for rotation with respect thereto, an eccentric throw securedto said shaft for rotation therewith, said throw being located withinsaid suction space, a bearing supported on the outer surface of saidthrow rotatable therewith, a slider block having a central openingreceiving said bearing, said bearing and throw driving said blockthrough oscillating movement with respect to the longitudinal axis ofsaid drive shaft, said block including a plurality of flat surfaces onthe outer periphery thereof, a piston in each of said cylinder boreshaving a base portion thereon formed aS a flat surface, each of saidbase portion surfaces engaging one of said slider surfaces on saidslider block for sliding movement therebetween upon oscillatory movementof said slider block about the longitudinal axis of said drive shaft, apin directed through each of said pistons, a link member having one endthereof connected to one end of a pin in one of said pistons and havingthe opposite end thereof connected to the end of a pin in another one ofsaid pistons, a second link member having one end thereof connected tothe opposite end of the pin in the one piston and the opposite endthereof connected to the opposite end of the pin in the another one ofsaid pistons, said first and second links having a central portionthereon offset from the connected ends of each of said links on eitherside of said shaft, each of said links prestressed between its connectedends to a length to hold said first and second pistons against saidslider block to maintain a close sliding fit therebetween upon rotationof the shaft, said slider block surfaces moving axially of and laterallyof each of said bores during oscillation of said slider block about saiddrive shaft during rotation thereof to produce reciprocation of saidfirst piston into and out of its cylinder bore in a direction oppositeto the reciprocation of said second piston within its cylinder bore andserving to define a flat surface support for said pistons at the basethereof to prevent tipping movement of said pistons with respect to saidcylinder bores during opposite reciprocation of said pistons within saidbores.
 3. In a reciprocating compressor the combination of, a centralbody, a plurality of radially outwardly directed cylinder bores in saidbody spaced 90* apart, the centerline of each of said cylinder boreslying in a common plane, a separate piston in each of said cylinderbores, a rotary drive shaft for said pistons, means for supporting saiddrive shaft for rotation with respect to said body, a common eccentricon said shaft for actuating each of said pistons, a slider blockoperated by said common eccentric, a flat surface on said slider blockin alignment with each of said pistons, means forming a flat followersurface on each of said pistons supportingly engaged by said flatsurface on said slider block, a first pair of said pistons locatedcoaxially of one another, a first pair of flat sheet metal connectinglinks located on each side of said second pair of pistons, each of saidlinks having a center portion offset from said shaft and ends secured tosaid first pair of pistons, each of said links being prestressed to apredetermined length between its opposite ends to locate said pistonstogether against said slider block, a second pair of said pistonslocated coaxially of one another and at right angles to said first pair,a second pair of flat sheet metal connecting links located on each sideof said second pair of pistons, each of said links having a centerportion offset from said shaft and ends secured to said second pair ofpistons, each of said links being prestressed to a predetermined lengthbetween its opposite ends to locate said second pair of pistons togetheragainst said slider block, said first and second pairs of sheet metalconnecting links maintaining the follower surface on each of saidpistons in close sliding fit relationship with the flat surfaces on saidslider block to produce opposite reciprocation of each of said pistonswithin its cylinder bore upon rotation of said shaft, said slider blockflat surface moving laterally and axially of said piston duringreciprocation thereof to define a stable supporting surface for saidpiston to prevent tipping movements thereof with respect to the cylinderbore during opposite reciprocation of said first and second pistonpairs.
 4. A compressor having a central body with a plurality ofradially outwardly directed cylinder bores therein, a piston in each ofsaid bores slidably reciprocable with respect thereto, said bodyincludinG a suction space located centrally thereof and radiallyinwardly of said bores, a plurality of discharge openings in said bodylocated radially outwardly of said suction space in spacedcircumferential relationship therearound, means for communicating saidsuction space and said discharge openings with said bores, a rearbearing housing secured to said body including means thereon closingsaid suction space in said body, a front bearing housing on said body, arotary shaft having the opposite ends thereof supportingly received insaid rear and front bearing housings, drive means for operativelyconnecting each of said pistons in said radial bores to said shafts forcausing opposite reciprocation of each of said pistons within one ofsaid radial bores during rotation of said shaft, said drive meansincluding an eccentric throw on said shaft, a bearing on the outerperiphery of said throw, a slider block supportingly received on thebearing having a portion thereon slidably engaging said pistons at aninterface for causing the opposite reciprocation thereof, means forlubricating said bearing and a sliding interface between said sliderblock and each of said pistons, said lubricating means including asuction port in said rear bearing housing formed coaxially of the end ofsaid shaft supported by said rear bearing housing, said rear bearinghousing having a transition bore aligned with said suction port forreducing velocity of inlet gas from said suction port, a large diameteropening in the supported end of said rotary shaft coaxially aligned withsaid suction port and transition bore and facing in the direction ofinlet gas flow through said suction port to separate and interceptlubricants suspended therein, a longitudinal passageway in said shaftfor receiving separated lubricant from the large diameter opening, atransverse passageway in said shaft receiving oil from the longitudinalpassageway to said bearing, and being rotated by said shaft todistribute oil in a radial direction, said slider block including aplurality of radially outwardly directed openings therein for directingoil from said bearing to the sliding interface between said slider blockand each of said pistons and into said suction space for lubricating thesurface during rotation of said shaft, said rear bearing housingincluding a pair of side ports intersected and communicated with saidtransition bore and said suction space, said side ports formed at anangle with respect to the longitudinal axis of said transition bore oneither side thereof for receiving gas from the suction port anddirecting it to the suction space in said body, and suction valve meansin each of said pistons for passage of gas and lubricant from thesuction space of said body into each of said radial bores.